pyaranet4 - Interface with your Aranet4 CO₂ meter via Python

This is a cross-platform interface for the Aranet4 CO₂ meter. You can use it to read values from the meter to then store in a database, display on a website, or generally do with whatever you want. Since the official mobile app for the device does not have automatic export features and the manual export is prone to failure, you can use this library instead for such purposes.

It is built with Bleak, a cross-platform Python Bluetooth client. It is also heavily inspired by Aranet4-Python, an excellent library that is unfortunately only compatible with Linux.

• Works on MacOS, Linux and Windows
• Command-line tool and Python library
• Lightweight: instantiate class, read class properties, done

Installation

pip install pyaranet4

Usage

Before you do anything, make sure the device is properly paired. Once it is paired, pyaranet4 will usually be able to figure out the rest (e.g. the MAC address) by itself. Note that Bluetooth LE is a slow protocol, and most commands and calls will take a couple of seconds to complete. This is not an issue with the library, but a limitation of the technology.

As a command-line tool

pyaranet4 comes with a command-line utility, which is mostly compatible with Aranet4-Python's:

C:\> pyaranet4
--------------------------------------
Connected: Aranet4 06CDC | v0.4.4
Updated 56 s ago. Intervals: 60 s
2167 total readings
--------------------------------------
CO2:         511 ppm
Temperature: 25.05 C
Humidity:    58 %
Pressure:    1014.50 hPa
Battery:     98 %
--------------------------------------

Get stored historical values from the device:

C:\> pyaranet4 --history
index,timestamp,temperature,humidity,pressure,co2
1,2021-09-09 22:12:20,25.1,56,1014.5,584
2,2021-09-09 22:13:20,25.1,56,1014.5,590
3,2021-09-09 22:14:20,25.1,56,1014.5,579
...

Or save them to a file:

C:\> pyaranet4 --history --output-file=readings.csv

Or view the full list of command-line arguments and parameters:

C:\> pyaranet4 --help

As a library

You can also use pyaranet4 as a library:

from pyaranet4 import Aranet4

a4 = Aranet4()
print("Battery level: %s%%" % a4.battery_level)
print("Current CO₂ level: %i ppm" % a4.current_readings.co2)
print("Stored CO2 values:")
print(a4.history.co2)

The Aranet4 object has the following public properties and methods:

• current_readings (namespace): The current readings of the device's sensors, as a namespace with properties co2 ( integer), temperature (float) pressure (float), humidity (integer), battery_level (integer) , update_interval (integer), and since_last_update (integer)
• current_readings_simple (namespace): Identical to current_readings, but without the update_interval and since_last_update properties; may be faster to request
• history (namespace): Historical readings stored on the device, as a namespace with properties co2, temperature , pressure, humidity, sensors, and timestamps. The sensor values are dictionaries with the interval index as keys and the sensor reading as values. sensors is a tuple of sensors included in the result. timestamps is a dictionary with indexes as keys and corresponding UNIX timestamps as values. The latter can be used to determine what the timestamp of a given value is.
• mac_address (string): The MAC address of the Bluetooth device
• battery_level (integer): Battery level, 0-100.
• manufacturer_name (string): The manufacturer of the device, e.g. SAF Tehnika
• model_name (string): The name of the device model, e.g. Aranet4
• device_name (string): The name of the device, e.g. Aranet4 06CDC
• hardware_revision (integer): Hardware revision number, e.g. 9
• software_revision (string): Software (firmware) version, e.g. v0.4.4
• update_interval (integer): Amount of seconds between sensor updates
• since_last_update (integer): Amount of seconds since last sensor update
• stored_readings_amount (integer): Amount of sensor readings stored on the device
• get_history(sensors: tuple, start: int, end: int) (namespace): Same return type as history, but allows one to limit results to a given tuple of sensors and a given range of indexes, which can be faster to receive than the full history. Sensors should be a tuple of a combination of Aranet4.SENSOR_CO2, Aranet4.SENSOR_HUMIDITY, and so on.